In recent years vehicle occupant safety has been a major concern of the automotive industry. While full size automobiles are sometimes used by the government and industry for final impact tests, it is generally impractical to use full size automobile for impact testing particularly during design and research stages necessary to ensure compliance with government mandated safety standards.
In order to comply with these safety standards, various impacts must be tested at various speeds. Thus, a multiplicity of vehicles must be subjected to a wide variety of crash conditions to obtain the necessary safety data and information.
For front end crash simulation, there has been available f,or some time a crash simulator apparatus known in the industry as a HYGE crash simulator. Said apparatus comprises a pressure differential firing means, utilizing both hydraulic and pneumatic pressures, which terminates in a thrust column. Upon actuation of the firing means, the thrust column accelerates a sled carriage suitably mounted on a track to be movable along said track. A test buck housing a forward facing vehicle occupant or driver specimen, generally in the form of an anthropomorphic dummy, is fixed mounted on the sled carriage. Acceleration of the sled carriage by the thrust column produces rapid acceleration of the movable sled carriage and thereby also of the test buck. As a result of the rapid acceleration of the sled carriage and test buck along the track, the occupant or driver test specimen is subjected to a rapid change in longitudinal velocity relative to the test buck thereby simulating a front end impact crash of an automobile vehicle. By using said HYGE crash simulator it is possible to reproduce essentially the crash conditions and parameters, such as a velocity-time profile, encountered by an occupant of a vehicle during a front end impact crash. Generally, in frontal crashes one has about an 80 millisecond period after the impact to establish the deceleration pattern typical of such frontal crashes. Deployment of test occupant airbags is to occur about 10 to 20 milliseconds after the impact.
More recently, side impact safety of vehicle occupants has become of increased concern and thus the necessity to test and evaluate side impact airbags. While at first blush it might seem apparent to simply rotate the test buck of a typical HYGE crash simulator by about 90.degree., so that it is placed sideways on the HYGE apparatus in order to produce lateral acceleration of an occupant to simulate the conditions and parameters of a side impact crash of an automobile, this has proved unsuccessful. One reason is that doing so does not enable one to produce essentially the crash conditions encountered during a side impact crash at 33 mph, the crash speed required under the presently mandated safety standards. For a side impact crash at 33 mph, the critical acceleration/deceleration pattern encountered is produced within about 30 milliseconds and deployment of a side impact airbag to be tested must occur about 5 milliseconds after impact. Simply turning the occupant-inhabited test buck sideways on such a HYGE crash simulator does not permit one to obtain the necessary acceleration of the test buck to about 20 mph within about a 20 milliseconds. Limitations in the sled carriage propulsion system prevent the test buck from reaching the velocity vs time profile needed to correctly simulate side impact crash tests.
It is therefore desirable to provide apparatus and methodology for developing the velocity vs time profile to produce the necessary dynamic parameters needed to more correctly simulate conditions of a side impact crash. A further object of this invention is to provide apparatus and methodology to more correctly simulate side impact crash conditions and to do so while using current accelerator type sled apparatus with modifications thereof. A still further object of this invention is to provide such apparatus and methodology while keeping all test components within the confines of the sled carriage of a HYGE type accelerator system and thereby minimizing, as much as possible, any requirement for use of additional equipment, controls, cameras and camera power and control and the like. Yet another object of this invention is to provide such apparatus and methodology such that no additional braking system would be required to perform post-test deceleration of the test structure.